Well, that may not be the best option. We don't know what software you used to update the firmware, how you connect this board to a PC or workstation, how the firmware is provided (downloaded from a site with instructions? handed to you on a USB drive?) etc..
There is a standard way of programming that microcontroller, but quite often people use bootloaders to allow for easier firmware updates (that doesn't require a hardware programmer specifically for that line of microcontrollers), and those are usually custom.
To me, it looks like it has a bootloader, which has either become corrupt, or the new firmware you are trying to update it with isn't compatible, or is rejected in some way.
So, firstly, what software do you use to update the firmware? And..
Is this whilst it is connected via USB? And..
Does that software provide options to reset the device to default?